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Patients FAQ Questions & Answers

How does Larval Therapy work?

A sealed bag containing live larvae is placed on the wound and the larvae pass a liquid secretion through small holes in the bag to break down any non-viable tissue in the wound into a liquid which they then ingest as nutrition.

Larvae do not have teeth meaning they cannot bite or chew. The liquid they produce cannot break down any healthy tissue and best of all the larvae stay in the bag for the full four day treatment.

Can larvae burrow into healthy tissue?

No, the larvae used in wound management (from the greenbottle fly species Lucilia sericata) have been carefully selected for their safety and predictability. They do not have any ability to dig, tunnel or burrow into the healthy tissue of humans, the secretions they produce cannot penetrate healthy tissue and they do not have teeth or any ability to break into viable and perfused tissue.

Will the larvae multiply in the wound?

No, larvae cannot mate, multiply or reproduce and are not on the wound long enough to begin the next stage of their life cycle which is pupation.

Larvae have a very predictable behaviour, all they do during the treatment is clean the wound and ingest the nutrition.

Where do the larvae come from?

Larvae are produced in a specialist aseptic manufacturing site in Bridgend, South Wales.

The green bottle flies are from a closed colony and are not collected from the wild. We provide the conditions for our flies to mate and the eggs they lay hatch into the larvae used for your wound dressing.

How big are the larvae?

When applied to your wound the larvae are only a few millimetres in length, around the size of an uncooked grain of rice. During the treatment they will increase in size as they clean the wound and will grow to around 10-12mm.

How are the larvae applied?

The larvae are sealed within a dressing which is a finely woven net called a BioBag – the BioBag is applied on your wound much like a standard dressing. The dressings come in five sizes and are applied according to the nature and size of the wound being treated. The larvae remain sealed within the dressing throughout the treatment.

You may have one or more BioBags placed on your wound and the treatment stays in place for up to four days. The BioBags are then taken off and are disposed of as clinical waste.

How long does the treatment last?

This can vary due to the nature of the wound considering factors such as the quantity of non-viable tissue, depth, infection level and circulation. Each BioBag dressing can be left in place for up to four days.

It is common for two to three treatments (four days each) to be required to help the wound progression. Some wounds require only one treatment whereas some more complex wounds may require four or more.

Are there any activities I should avoid during treatment?

Although it is possible for you to carry out most of your normal activities whilst undergoing Larval Therapy, you should ideally not bathe, shower, or immerse the wound in water.  It is not advisable to cover the dressing in a plastic dressing protector as this can reduce larval viability. The BioBag dressing can be removed and reapplied for the purposes of a bath or a shower.

It is also not advisable to sit with the wound too close to a source of heat e.g., fire or a radiator, as the larvae may dry out. Similarly, sitting, lying, or walking on a wound treated with larvae should also be avoided as this can reduce the effectiveness of the treatment.

Does it hurt? Will I feel it?

Most people do not feel anything however it would be normal to feel a tingling, pulsating or tickling sensation. Some patients do experience a change in sensation over the four-day period as the larvae remove the dead tissue and reveal the nerves in the wound bed.

People who already have a painful or sensitive wound, such as with limb ischaemia or circulatory issues (especially in wounds above the ankle and below the knee) are likely to experience an increase in wound pain.

The larvae are not biting the wound so any increase in pain is thought to be related to the healing process and nerve stimulation. If you are concerned about the risk of wound pain, please speak to your Healthcare Professional as in most cases prescribed pain relief is sufficient to reduce or prevent pain.

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